Cell Membrane And Transport

Question 1

What is the primary function of the cell membrane?

Answer 1

• regulate transport of solutes
• detect and transmit electrical and chemical signals
• site of specific proteins with specific functions

Question 2

True or False: The cell membrane is composed of a single layer of lipids.

Answer 2

False

Question 3

Fill in the blank: The cell membrane is primarily made up of ______ and proteins.

Answer 3

phospholipids

Question 4

What model describes the structure of the cell membrane?

Answer 4

Fluid mosaic model

Question 5

Which type of transport does not require energy?

Answer 5

Passive transport

Question 6

What is the role of cholesterol in the cell membrane?

Answer 6

To maintain membrane fluidity and stability.

Question 7

True or False: Osmosis is the movement of water across a selectively permeable membrane.

Answer 7

True

Question 8

What is the process by which cells take in large particles called?

Answer 8

Endocytosis

Question 9

Which type of protein helps transport substances across the cell membrane?

Answer 9

Transport proteins

Question 10

What is the term for the movement of molecules from an area of higher concentration to an area of lower concentration?

Answer 10

Diffusion

Question 11

Fill in the blank: The _______ is a semi-permeable barrier that allows certain substances to pass while blocking others.

Answer 11

cell membrane

Question 12

What is the main difference between facilitated diffusion and simple diffusion?

Answer 12

Facilitated diffusion requires specific transport proteins.

Question 13

True or False: Active transport moves substances against their concentration gradient.

Answer 13

True

Question 14

What is the function of aquaporins in the cell membrane?

Answer 14

To facilitate water transport.

Question 15

Which type of solution causes a cell to swell?

Answer 15

Hypotonic solution

Question 16

What is exocytosis?

Answer 16

The process by which a cell expels materials in vesicles.

Question 17

Fill in the blank: The phospholipid bilayer is composed of hydrophilic ______ and hydrophobic ______.

Answer 17

heads; tails

Question 18

What are glycoproteins and glycolipids important for?

Answer 18

Cell recognition and communication.

Question 19

Which ion is often actively transported out of cells?

Answer 19

Sodium (Na+)

Question 20

What does it mean if a cell is in a hypertonic solution?

Answer 20

The solution has a higher concentration of solutes than the inside of the cell.

Question 21

What is the primary role of receptor proteins in the cell membrane?

Answer 21

To bind to signaling molecules and initiate a cellular response.

Question 22

True or False: The cell membrane is impermeable to all substances.

Answer 22

False

Question 23

What is the role of the sodium-potassium pump?

Answer 23

To maintain the electrochemical gradient by pumping sodium out and potassium in.

Question 24

Fill in the blank: ______ transport requires energy in the form of ATP.

Answer 24

Active

Question 25

What happens to a cell in an isotonic solution?

Answer 25

There is no net movement of water; the cell remains the same size.

Question 26

What type of molecules can easily pass through the lipid bilayer?

Answer 26

Small, nonpolar molecules.

Question 27

Which process involves the engulfing of large particles by the cell membrane?

Answer 27

Phagocytosis

Question 28

Difference between glycoprotein and glycolipid

Answer 28

Glycoprotein: oligasaccharide attached to protein Glycolipid: attached to lipid

Question 29

Fluidity of membranes refers to the ... of the lipid bilayer of the cell membrane

Answer 29

Viscosity

Question 30

What does temperature got to do with membrane fluidity

Answer 30

Increase in temp: increase in fluidity, melt Decrease in temp: opp

Question 31

What does an increase in length of fatty acid chain got to do with fluidity of the membrane

Answer 31

Increase length, increase optimum temp, decrease fluidity Decrease length, decrease optimum temp, increase fluidity

Question 32

What has transition temp got to do with fluidity of the membrane

Answer 32

Temp>Tm: more fluid Temp

Question 33

What has number of double bonds got to do with fluidity of the membrane

Answer 33

More double bond: more fluid Less double bond: opp

Question 34

Difference between active and passive transport

Answer 34

Active: uses atp, low-high concentration Passive: no atp, high-low concentration

Question 35

Example of passive transport

Answer 35

Diffusion

Question 36

Example of active transport

Answer 36

Bulk transport (endocytosis, exocytosis)

Question 37

What is simple diffusion

Answer 37

Movement of small and polar molecules from high-low concentration

Question 38

What is facilitated diffusion

Answer 38

(Simple Diffusion) + big polar molecules

Question 39

Features of facilitated diffusion

Answer 39

- ion channels: channel proteins allow specific ions to pass through Gated channels (open when there is a stimulus and protein change shape) - ligand-gated: ligand - voltage-gated: change in electrical charge diff across membrane

Question 40

Factors affecting rate of diffusion

Answer 40

- increase concentration gradient, increase speed diffusion - increase temp, increase speed diffusion - decrease molecule diameter, increase speed diffusion - decrease membrane thickness, increase speed diffusion - more surface area, faster diffusion

Question 41

What is osmosis

Answer 41

Movement of water across cell membrane

Question 42

What is water potential

Answer 42

Measure of potential energy of water

Question 43

Water potential factors

Answer 43

- dilute solution: high concentration of water molecules, high water potential - concentrated: opp

Question 44

What does it mean when a solution is hypotonic

Answer 44

Solution has lower concentration of solute than cell

Question 45

What is meant by a hypertonic solution

Answer 45

Solution has higher concentration of solute than cell

Question 46

What is meant by an isotonic solution

Answer 46

Same solute concentration

Question 47

Stages of cell signalling

Answer 47

1. Secretion of ligands 2. Transport of ligands to target cell 3. Ligands binding to cell surface receptor on target cells

Question 48

What are the 2 types of receptors

Answer 48

1. Intracellular: hydrophobic ligands, lipid-soluble 2. Cell-surface: opp

Question 49

factors of water potential

Answer 49

more solute: less water potential less solute: more water potential

Question 50

carrier proteins

Answer 50

transport of larger polar molecules by active oe passive transport

Question 51

substances that can directly pass through cell surface membranes

Answer 51

oxygen, water, carbon dioxide

Question 52

mosaic meaning

Answer 52

protein moleculea floating around the membrane

Question 53

fluid meaning

Answer 53

membrane moves and isn't stiff